4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jia-Ju Bai <[email protected]> [ Upstream commit 343eba69c6968190d8654b857aea952fed9a6749 ] The kernel may sleep under a rcu read lock in tipc_msg_reverse, and the function call path is: tipc_l2_rcv_msg (acquire the lock by rcu_read_lock) tipc_rcv tipc_sk_rcv tipc_msg_reverse pskb_expand_head(GFP_KERNEL) --> may sleep tipc_node_broadcast tipc_node_xmit_skb tipc_node_xmit tipc_sk_rcv tipc_msg_reverse pskb_expand_head(GFP_KERNEL) --> may sleep To fix it, "GFP_KERNEL" is replaced with "GFP_ATOMIC". Signed-off-by: Jia-Ju Bai <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/tipc/msg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/tipc/msg.c +++ b/net/tipc/msg.c @@ -508,7 +508,7 @@ bool tipc_msg_reverse(u32 own_node, str } if (skb_cloned(_skb) && - pskb_expand_head(_skb, BUF_HEADROOM, BUF_TAILROOM, GFP_KERNEL)) + pskb_expand_head(_skb, BUF_HEADROOM, BUF_TAILROOM, GFP_ATOMIC)) goto exit; /* Now reverse the concerned fields */
